Multi-layered ceramic capacitor and method of manufacturing the same

ABSTRACT

A multilayer ceramic capacitor includes a ceramic body including a dielectric layer and first and second internal electrodes disposed to oppose each other with the dielectric layer interposed therebetween, and first and second external electrodes disposed outside of the ceramic body and connected to the first and second internal electrodes, respectively. The ceramic body includes an active portion including of the first and second internal electrodes disposed to oppose each other with the dielectric layer interposed therebetween to form capacitance, and a cover portion disposed in upper and lower portions of the active portion. The cover portion has a larger number of pores than the dielectric layer of the active portion, and the cover portion includes a ceramic-polymer composite filled with a polymer in the pores of the cover portion.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is the continuation application of U.S. patentapplication Ser. No. 17/835,053 filed on Jun. 8, 2022, which is thedivisional application of U.S. patent application Ser. No. 16/816,666filed on Mar. 12, 2020, which claims benefit of priority to KoreanPatent Application No. 10-2019-0103621 filed on Aug. 23, 2019 in theKorean Intellectual Property Office, the disclosure of which isincorporated herein by reference in its entirety.

BACKGROUND 1. Field

The present disclosure relates to a multilayer ceramic capacitor and amethod of manufacturing the same.

2. Description of Related Art

Generally, an electronic component using a ceramic material such as acapacitor, an inductor, a piezoelectric device, a varistor, athermistor, or the like, may include a ceramic body formed of a ceramicmaterial, an internal electrode formed inside the ceramic body, and anexternal electrode disposed on a surface of the ceramic body to beconnected to the internal electrode.

A multilayer ceramic capacitor, an electronic component, is anelectronic component having chip form, used for charging or dischargingelectricity in various electronic circuit systems in the field ofelectric electronic components including information technology (IT),entertainment systems, powertrain systems, electronic control units(ECU), and the like.

Since electric multilayer ceramic capacitors are used in harshenvironments, high reliability and durability are required therein.

In particular, reliability characteristics according to temperature andhumidity in a high-temperature and high-humidity environment must beexcellent, and mechanical characteristics able to withstand bendingdeformation of a mounting substrate due to vibrations and otherrequirements of a vehicle body must be excellent.

Conventionally, in order to enhance bending strength, an improvement ofhardness of a body of the multilayer ceramic capacitor or a developmentof a technology for the external electrode has mainly been made. Assuch, a need exists for development of cover portions and/or marginportions that provide enhanced bending strength.

SUMMARY

An aspect of the present disclosure is to provide a multilayer ceramiccapacitor capable of improving reliability and a method of manufacturingthe same.

According to an aspect of the present disclosure, a multilayer ceramiccapacitor includes a ceramic body including a dielectric layer and firstand second internal electrodes disposed to oppose each other with thedielectric layer interposed therebetween, and having a first surface anda second surface opposing each other, a third surface and a fourthsurface opposing each other and connecting the first and secondsurfaces, and a fifth surface and a sixth surface connected to the firstto fourth surfaces and opposing each other, and first and secondexternal electrodes disposed outside of the ceramic body and connectedto the first and second internal electrodes, respectively. The ceramicbody includes an active portion including the first and second internalelectrodes disposed to oppose each other with the dielectric layerinterposed therebetween to form capacitance, and a cover portiondisposed in upper and lower portions of the active portion. The coverportion has a larger number of pores than the dielectric layer of theactive portion, and the cover portion includes a ceramic-polymercomposite filled with a polymer in the pores of the cover portion.

According to another aspect of the present disclosure, a method ofmanufacturing a multilayer ceramic capacitor includes preparing aplurality of first ceramic green sheets on which a plurality of firstinternal electrodes are disposed and a plurality of first ceramic greensheets on which a plurality of second internal electrodes are disposed,alternately stacking the first ceramic green sheets having the first andsecond internal electrode patterns so that the first internal electrodepatterns and the second internal electrode patterns overlap each other,and stacking second ceramic green sheets having a composition differentfrom the composition of the first ceramic green sheets on upper andlower portions thereof to form a laminated body. A ceramic body isprepared including dielectric layers and first and second internalelectrodes by sintering the laminated body. The ceramic body includes anactive portion including first and second internal electrodes disposedto oppose each other with the dielectric layers interposed therebetweento form capacitance and a cover portion disposed in upper and lowerportions of the active portion. The cover portion has a larger number ofpores than the dielectric layer of the active portion. After thepreparing of the ceramic body, a paste including a polymer is applied tothe cover portion to fill the pores of the cover portion with thepolymer is included.

According to further aspect of the present disclosure, a multilayerceramic capacitor includes a ceramic body including a plurality of firstinternal electrodes and a plurality of second internal electrodes thatare alternately stacked with dielectric layers therebetween. The ceramicbody includes upper and lower cover portions respectively disposed abovean uppermost internal electrode and below a lowermost internal electrodeof the first and second internal electrodes, and the upper and lowercover portions include a higher content of polymer than the dielectriclayers disposed between the alternately stacked first and secondinternal electrodes.

According to another aspect of the present disclosure, a multilayerceramic capacitor includes a ceramic body including a plurality of firstinternal electrodes and a plurality of second internal electrodes thatare alternately stacked to overlap each other in a thickness directionwith dielectric layers therebetween. The first and second internalelectrodes are spaced apart by a margin portion from side surfaces ofthe ceramic body opposite each other in a width direction orthogonal tothe thickness direction, and the margin portion includes a highercontent of polymer than the dielectric layers disposed between thealternately stacked first and second internal electrodes.

BRIEF DESCRIPTION OF DRAWINGS

The above and other aspects, features, and advantages of the presentdisclosure will be more clearly understood from the following detaileddescription taken in conjunction with the accompanying drawings, inwhich:

FIG. 1 is a schematic perspective view illustrating a multilayer ceramiccapacitor according to an embodiment of the present disclosure;

FIG. 2 is a cross-sectional view taken along line I-I′ of FIG. 1 ;

FIG. 3 is a cross-sectional view taken along line II-II′ of FIG. 1 ;

FIG. 4 is an enlarged view of region A of FIG. 2 ;

FIG. 5 is a cross-sectional view taken along the line II-II′ of FIG. 1according to another embodiment of the present disclosure;

FIG. 6 is an enlarged view of region B of FIG. 5 ;

FIG. 7 is a cross-sectional view taken along the line II-II′ of FIG. 1according to another embodiment of the present disclosure; and

FIG. 8 is a schematic diagram illustrating an operation of filling apolymer in pores of a cover portion in a method of manufacturing amultilayer ceramic capacitor according to an embodiment of the presentdisclosure.

DETAILED DESCRIPTION

Hereinafter, embodiments of the present disclosure will be described indetail with reference to the accompanying drawings. The presentdisclosure may, however, be exemplified in many different forms andshould not be construed as being limited to the specific embodiments setforth herein. Rather, these embodiments are provided so that thisdisclosure will be thorough and complete, and will fully convey thescope of the disclosure to those skilled in the art. In the drawings,the shapes and dimensions of elements may be exaggerated for clarity.Further, in the drawings, elements having the same functions within thesame scope of the inventive concept will be designated by the samereference numerals.

FIG. 1 is a schematic perspective view illustrating a multilayer ceramiccapacitor according to an embodiment of the present disclosure.

FIG. 2 is a cross-sectional view taken along line I-I′ of FIG. 1 .

FIG. 3 is a cross-sectional view taken along line II-II′ of FIG. 1 .

FIG. 4 is an enlarged view of region A of FIG. 2 .

Referring to FIGS. 1 to 4 , a multilayer ceramic capacitor 100 accordingto an embodiment of the present disclosure may include a ceramic body110, a plurality of internal electrodes 121 and 122 formed in theceramic body 110, and external electrodes 131 and 132 formed on an outersurface of the ceramic body 110.

The ceramic body 110 may have a first surface 1 and a second surface 2opposing each other, a third surface 3 and a fourth surface 4 opposingeach other and connected to the first and second surfaces 1 and 2, and afifth surface 5 and a sixth surface 6, which are upper and lowersurfaces opposing each other and connected to the first, second, third,and fourth surfaces.

The first surface 1 and the second surface 2 may be defined as surfacesopposing each other in a width direction of the ceramic body 110, thethird surface 3 and the fourth surface 4 may be defined as surfacesopposing each other in a longitudinal or length direction, and the fifthsurface 5 and the sixth surface 6 may be defined as surfaces opposingeach other in a thickness direction.

The shape of the ceramic body 100 is not particularly limited, but maybe a rectangular parallelepiped shape as shown.

One end of each of the plurality of internal electrodes 121 formed inthe ceramic body 110 may be exposed to the third surface 3, and one endof each of the plurality of internal electrodes 122 formed in theceramic body 110 may be exposed to the fourth surface 4 of the ceramicbody.

The internal electrodes 121 and 122 may be formed as pairs of the firstinternal electrode 121 and the second internal electrode 122 havingdifferent polarities and separated from each other by a dielectric layer111.

One end of each first internal electrode 121 may be exposed to the thirdsurface 3, and one end of each second internal electrode 122 may beexposed to the fourth surface 4.

The ends of the first internal electrode 121 and the second internalelectrode 122 opposite to the exposed ends may be disposed at apredetermined distance inside the ceramic body 110 from the fourthsurface 4 and the third surface 3, respectively.

A first external electrode 131 may be formed on the third surface 3 ofthe ceramic body to be electrically connected to the first internalelectrode(s) 121, and a second external electrode 132 may be formed onthe fourth surface 4 of the ceramic body to be electrically connected tothe second internal electrode(s) 122.

The first and second external electrodes 131 and 132 may be electricallyconnected to the first and second internal electrodes 121 and 122,respectively, to form capacitance, and the second external electrode 132may be connected to a potential different from the first externalelectrode 131.

The plurality of dielectric layers 111 are in a sintered state, and thedielectric layers 111 may be integrated with each other such that it maybe difficult to identify boundaries between adjacent dielectric layers111 with the naked eye.

A length of the ceramic body 110 corresponds to a distance from thethird surface 3 to the fourth surface 4 of the ceramic body.

According to an embodiment of the present disclosure, a raw material forforming the dielectric layer 111 is not particularly limited as long assufficient capacitance can be obtained therewith. For example, a bariumtitanate based material, a lead composite perovskite based material, astrontium titanate based material, or the like can be used.

As a material for forming the dielectric layer 111, various ceramicadditives, organic solvents, plasticizers, binders, dispersants, and thelike, may be added to powder such as barium titanate (BaTiO₃) accordingto the purpose of the present disclosure.

Internal electrodes 121 and 122 may be formed on the dielectric layers111, and the internal electrodes 121 and 122 may be formed in theceramic body with one dielectric layer 111 interposed therebetween bysintering.

Referring to FIG. 2 , a first internal electrode 121 is formed in thedielectric layer 111. The first internal electrode 121 is not entirelyformed in a longitudinal direction of the dielectric layer. That is, oneend of the first internal electrode 121 may be formed at a predetermineddistance from the fourth surface 4 of the ceramic body, and the otherend of the first internal electrode 121 may be formed to extend to thethird surface 3 and be exposed to the third surface

An end portion of the first internal electrode 121 exposed to the thirdsurface 3 of the ceramic body is connected to the first externalelectrode 131.

In contrast to the first internal electrode, one end of the secondinternal electrode 122 may be formed at a predetermined distance fromthe third surface 3, and the other end of the second internal electrode122 may be exposed to the fourth surface 4 and connected to the secondexternal electrode 132.

The internal electrodes may be stacked in more than 400 layers toimplement a high-capacity multilayer ceramic capacitor, but is notnecessarily limited thereto.

The ceramic body 110 may be composed of an active portion serving as aportion contributing to capacitance formation and including the internalelectrodes 121 and 122, and upper and lower cover portions 112 and 113formed in the upper and lower portions of the active portion as upperand lower margin parts, respectively. The upper and lower cover portions112 and 113 may be free of any internal electrodes, and may be disposedabove an uppermost internal electrode and below a lowermost internalelectrode, respectively, in the ceramic body 110.

The active portion may be formed by repeatedly and alternately stackingthe first and second internal electrodes 121 and 122 with the dielectriclayers 111 interposed therebetween.

The upper and lower cover portions 112 and 113 are similar to thedielectric layer 111 except that they do not include internalelectrodes, but according to an embodiment of the present disclosure, adielectric composition of the cover portion(s) and a dielectriccomposition of the dielectric layer(s) of the active portion may bedifferent from each other.

That is, the upper and lower cover portions may include a ceramicmaterial, for example, may include a barium titanate (BaTiO₃) basedceramic material.

According to an embodiment of the present disclosure, to form a coverportion of a porous structure in which pores of the upper and lowercover portions 112 and 113 after sintering are more numerous than (e.g.,are provided at a higher density than) pores of the dielectric layer(s)111 of the active portion, the dielectric composition of the upper andlower cover portions 112 and 113 may be different in types and contentsof additives or binders, with respect to the dielectric composition ofthe dielectric layer(s) 111 of the active portion.

For example, a method may be used to adjust the content of magnesium(Mg) included in the upper and lower cover portions 112 and 113 to beless than the content of magnesium (Mg) included in the dielectric layer111 of the active portion.

Alternatively, the binder used to form the dielectric layer 111 of theactive portion may use a polyvinyl butyral (PVB) based binder as in theprior art, and the binder used to form the upper and lower coverportions 112 and 113 may use an acryl-based binder.

Referring to FIG. 4 , in the multilayer ceramic capacitor according toan embodiment of the present disclosure, the upper and lower coverportions 112 and 113 may have a larger number or higher density of poresP than the dielectric layer 111 of the active portion, and the upper andlower cover portions 112 and 113 may include a ceramic-polymer compositein which a polymer 140 is filled in the pores P of the upper and lowercover portions 112 and 113.

According to an embodiment of the present disclosure, the upper andlower cover portions 112 and 113 may have a porous structure in whichthe pores of the upper and lower cover portions 112 and 113 aftersintering are more numerous than the pores of the dielectric layer 111,and a polymer is filled in the pores of the upper and lower coverportions 112 and 113, such that the upper and lower cover portions 112and 113 may be formed to have a ceramic-polymer composite structure,thereby improving bending strength and improving moisture resistancereliability, at the same time.

In detail, when the polymer is filled in the pores of the upper andlower cover portions 112 and 113 and the upper and lower cover portions112 and 113 are formed to have a ceramic-polymer composite structure,since ductility of the upper and lower cover portions 112 and 113 isimproved, bending strength may be improved, and at the same time,moisture resistance reliability may be improved.

In addition, by forming the upper and lower cover portions 112 and 113with a ceramic-polymer composite structure, it is possible to solve aproblem of lowering the moisture resistance reliability due to thetransfer of charges by reducing electrical conductivity.

According to an embodiment of the present disclosure, a polymer may notbe filed in the pores in the dielectric layer 111 of the active portion.

According to an embodiment of the present disclosure, in order toimprove bending strength and improve the moisture resistance reliabilityof the electric multilayer ceramic capacitor, since the upper and lowercover portions 112 and 113 are formed in a porous structure aftersintering, and the polymer 140 is filled in the pores P of the upper andlower cover portions 112 and 113, the pores in the dielectric layer 111of the active portion may not be filled with the polymer.

In the conventional multilayer ceramic capacitor there has been anattempt to include a dielectric layer made of a composite material inwhich ceramic powder and a polymer are mixed.

However, in order to include the dielectric layer made of a compositematerial mixed with ceramic powder and a polymer, the ceramic body maynot be fired, and when a sintering process is performed, the polymer maybe lost in a high-temperature sintering process and may generally notremain in a final product, and thus, an effect due to the polymer maynot be obtained.

According to an embodiment of the present disclosure, since a ceramicbody is fired differently from the prior art, and a polymer 140 isfilled in the pores P of the upper and lower cover portions 112 and 113after sintering, the polymer 140 may remain in a cover portion of themultilayer ceramic capacitor and may constitute a ceramic-polymercomposite.

On the other hand, pores in the dielectric layer 111 of the activeportion have a structure in which a polymer is not filled.

As described above, according to an embodiment of the presentdisclosure, since the polymer is filled in the pores of the coverportion(s) after the sintering process is performed, ductility of theupper and cover portions 112 and 113 may be improved, thereby obtainingan effect of improving bending strength and improving moistureresistance reliability.

Meanwhile, referring to FIG. 4 , in the multilayer ceramic capacitoraccording to an embodiment of the present disclosure, a thickness td ofthe dielectric layer 111 and a thickness te of the internal electrodes121 and 122 may satisfy td>2×te.

That is, according to an embodiment of the present disclosure, thethickness td of the dielectric layer 111 may be equal to twice or morethe thickness te of the internal electrodes 121 and 122.

In general, in high-voltage electric electronic components, areliability problem caused by a drop in a dielectric breakdown voltagein a high-voltage environment is a major issue.

In the multilayer ceramic capacitor according to an embodiment of thepresent disclosure, the thickness td of the dielectric layer 111 may beequal to twice or more the thickness te of the internal electrodes 121and 122 to prevent lowering of the dielectric breakdown voltage in harshenvironments, such that the dielectric breakdown voltage characteristicmay be improved by increasing the thickness of the dielectric layer,which may correspond to an increase in a distance between the internalelectrodes.

When the thickness td of the dielectric layer 111 is twice or less thanthe thickness te of the internal electrodes 121 and 122, the thicknessof the dielectric layer (corresponding to a distance between theinternal electrodes) may be thin, thereby lowering the dielectricbreakdown voltage.

The thickness te of the internal electrode may be less than 1 μm, andthe thickness td of the dielectric layer may be less than 2.8 μm, but isnot necessarily limited thereto.

FIG. 5 is a cross-sectional view taken along the line II-II′ of FIG. 1according to another embodiment of the present disclosure.

FIG. 6 is an enlarged view of region B of FIG. 5 .

Referring to FIGS. 5 and 6 , in the multilayer ceramic capacitoraccording to another embodiment of the present disclosure, marginportions 114 and 115 may be disposed on one or both opposing sidesurface(s) of the active portion.

The margin portions may be comprised of a first margin portion 114disposed on the first surface 1 of the ceramic body 110 and a secondmargin portion 115 disposed on the second surface 2.

The margin parts 114 and 115 may have a larger number of pores than thedielectric layer 111 of the active portion 111.

In order to form margin parts 114 and 115 of a porous structure aftersintering having the pores of the margin parts 114 and 115 aftersintering that are more numerous than the pores of the dielectric layer111 of the active portion, the dielectric composition of the marginportions 114 and 115 may be different in types and contents of anadditive or a binder, with respect to the dielectric composition of thedielectric layer 111 of the active portion.

For example, there may be a method of adjusting an amount of magnesium(Mg), included in the margin parts 114 and 115 to be less than a contentof magnesium (Mg) included in the dielectric layer 111 of the activeportion.

Alternatively, there may be a problem in which the binder used to formthe dielectric layer 111 of the active portion uses a polyvinyl butyral(PVB) based binder as in the prior art, and the binder used to form themargin parts 114 and 115 uses an acryl-based binder.

In the present embodiment, the dielectric composition of the marginportions 114 and 115 may be different from the dielectric composition ofthe dielectric layer 111 of the active portion, and at the same time,the dielectric composition of the margin portions 114 and 115 may bedifferent from that the dielectric composition of the upper and lowercover portions 112 and 113, but is not necessarily limited thereto.

Referring to FIG. 6 , in a multilayer ceramic capacitor according toanother embodiment of the present disclosure, the margin portions 114and 115 may have a larger number or density of pores P than thedielectric layer 111 of the active portion, and the margin portions 114and 115 may include a ceramic-polymer composite in which the polymer 140is filled in the pores P of the margin portions 114 and 115.

According to an embodiment of the present disclosure, margin portions114 and 115 of a porous structure in which pores of the margin portions114 and 115 after sintering are more numerous than pores of thedielectric layer 111 of the active portion may be formed, and the poresof the margin portions 114 and 115 may be filled with a polymer, and themargin portions 114 and 115 may be formed to have a ceramic-polymercomposite structure, thereby improving bending strength and at the sametime improving moisture resistance reliability.

Specifically, when the polymer is filled in the pores of the marginportions 114 and 115 and the margin portions 114 and 115 are formed tohave a ceramic-polymer composite structure, since ductility of themargin portions 114 and 115 may be improved, the bending strength may beimproved, and at the same time, the moisture resistance reliability maybe improved.

In addition, by forming the margin portions 114 and 115 in aceramic-polymer composite structure, it is possible to solve a problemof lowering the moisture resistance reliability due to a transfer ofcharges by reducing electrical conductivity.

FIG. 7 is a cross-sectional view taken along the line II-II′ of FIG. 1according to another embodiment of the present disclosure.

Referring to FIG. 7 , in another embodiment of the present disclosure,the dielectric composition of the upper and lower cover portions 112 and113 may be different from the dielectric composition of the dielectriclayer 111 of the active portion, but may be the same as the dielectriccomposition of the margin portions 114 and 115.

Since other features are the same as in the above-described otherembodiments of the present disclosure, a detailed description thereofwill be omitted.

A method of manufacturing a multilayer ceramic capacitor according toanother embodiment of the present disclosure includes operations of:preparing a plurality of first ceramic green sheets on which a pluralityof first internal electrode patterns are formed and a plurality of firstceramic green sheets on which a plurality of second internal electrodepatterns are formed; stacking the plurality of first ceramic greensheets so that the first internal electrode patterns and the secondinternal electrode patterns overlap with each other, and stacking asecond ceramic green sheet having a composition different from thecomposition of the first ceramic green sheet on upper and lower portionsthereof to form a laminated body, and preparing a ceramic body includinga dielectric layer and first and second internal electrodes by sinteringthe laminated body. The ceramic body includes an active portionincluding first and second internal electrodes disposed to oppose eachother with the dielectric layer interposed therebetween to formcapacitance and a cover portion formed in upper and lower portions ofthe active portion, and the cover portion has a larger number or densityof pores than that of the dielectric layer of the active portion. Afterthe operation of preparing the ceramic body, an operation of applying apaste including a polymer to the cover portion to fill the pores of thecover portion with the polymer is included.

Hereinafter, a method of manufacturing a multilayer ceramic capacitoraccording to another embodiment of the present disclosure will bedescribed.

According to another aspect of the present disclosure, there is provideda method of manufacturing a multilayer ceramic capacitor. First, aplurality of first ceramic green sheets on which a plurality of firstinternal electrode patterns are formed and a plurality of first ceramicgreen sheets on which a plurality of second internal electrode patternsare formed.

The plurality of first ceramic green sheets may be formed of a ceramicpaste including ceramic powder, an organic solvent, and an organicbinder.

The ceramic powder is a material having a high dielectric constant, butis not limited thereto, and may be a barium titanate (BaTiO₃) basedmaterial, a lead composite perovskite based material, or the like, andmay be preferably barium titanate (BaTiO₃) powder. When the ceramicgreen sheet 211 is fired, the ceramic green sheet 211 becomes adielectric layer 111 constituting the ceramic body 110.

The first internal electrode pattern and the second internal electrodepattern may be formed by an internal electrode paste including aconductive metal. The conductive metal is not limited thereto, but maybe nickel (Ni), copper (Cu), palladium (Pd), or an alloy thereof.

A method of forming the first internal electrode pattern and the secondinternal electrode pattern on the first ceramic green sheet is notparticularly limited, but may be formed by, for example, a printingmethod such as a screen-printing method or a gravure printing method.

Next, the plurality of first ceramic green sheets are stacked to overlapthe first internal electrode pattern and the second internal electrodepattern, and second ceramic green sheets having a composition differentfrom the composition of the first ceramic green sheet are disposed onupper and lower portions thereof to form a laminated body.

The second ceramic green sheets having a composition different from thatof the first ceramic green sheet is used to form upper and lower coverlayers by stacking the plurality of second ceramic green sheets on theupper and lower portions of the laminated body.

In an embodiment of the present disclosure, the second ceramic greensheets have a composition different from that of the first ceramic greensheet in order to have a porous structure in which the pores of theupper and lower cover layers after sintering are more numerous than(e.g., are disposed with higher density than) the pores of thedielectric layer of the active portion.

In addition, since the second ceramic green sheets are used to formupper and lower cover layers, internal electrode patterns are not formedthereon, unlike the first ceramic green sheet.

Next, a ceramic body including a dielectric layer and first and secondinternal electrodes is prepared by sintering the laminated body.

By sintering the laminated body, the ceramic body includes an activeportion including first and second internal electrodes disposed tooppose each other with the dielectric layer interposed therebetween toform capacitance, and a cover portion formed in upper and lower portionsof the active portion.

In an embodiment of the present disclosure, as described above, sincethe second ceramic green sheet for forming the upper and lower coverlayers has a composition different form the composition of the firstceramic green sheet for forming the dielectric layer, the cover portionafter sintering has a porous structure having a larger number of poresthan the dielectric layer of the active portion.

FIG. 8 is a schematic diagram illustrating an operation of filling apolymer in pores of a cover portion in a method of manufacturing amultilayer ceramic capacitor according to an embodiment of the presentdisclosure.

Referring to FIG. 8 , in the method of manufacturing the multilayerceramic capacitor according to an embodiment of the present disclosure,a paste including a polymer is applied to the cover portion after anoperation of preparing the ceramic body, after sintering is completed,to fill pores of the cover portion with the polymer.

A method of applying the paste including the polymer to the coverportion is not particularly limited, and may be performed by, forexample, a dipping, a spin coating, a spraying method, and the like.

It is preferable to use a liquid crystal polymer (LCP), which is a highheat-resistance thermoplastic resin, as the polymer. Such a liquidcrystal polymer may be an aromatic liquid crystal polyester.

When performed by the method, the polymer 240 is applied above adielectric grain 211 of the cover portion, and then the polymer 240 willbe filled in pores formed between the dielectric grains 211 of the coverportion by a post-treatment process.

The post-treatment process may be performed after the operation offilling the polymer in the pores of the cover portion, and may beperformed using any one or more of heat, UV, IR, and laser.

Subsequently, external electrodes may be formed on a third side surfaceof the ceramic body to which the first internal electrode is exposed anda fourth side surface of the ceramic body to which the second internalelectrode is exposed.

Description of the same parts as the features of the embodiment of thepresent disclosure described above will be omitted here in order toavoid duplication.

As set forth above, according to an embodiment of the presentdisclosure, a cover portion may be formed to have a porous structure inwhich pores of the cover portion after sintering are more numerous thanpores of the dielectric layer of the active portion, and the pores ofthe cover portion may be filled with a polymer and the cover portion maybe formed of a ceramic-polymer composite structure, such that it ispossible to improve bending strength and improve the moisture resistancereliability.

In addition, by forming the cover portion in a ceramic-polymer compositestructure, it is possible to reduce electrical conductivity and solve aproblem of lowering moisture resistance reliability due to a transfer ofcharges.

In addition, after sintering, a margin part may be formed to have aporous structure in which pores of the margin part after sintering aremore numerous than pores of the dielectric layer of the active portion,and the margin part may be formed of a ceramic-polymer compositestructure by filling the pores of the margin part with a polymer, suchthat bending strength may be improved and moisture resistancereliability may be improved.

What is claimed is:
 1. A multilayer ceramic capacitor, comprising: aceramic body including a dielectric layer and first and second internalelectrodes disposed to oppose each other with the dielectric layerinterposed therebetween, and having a first surface and a second surfaceopposing each other, a third surface and a fourth surface opposing eachother and connecting the first and second surfaces, and a fifth surfaceand a sixth surface connected to the first to fourth surfaces andopposing each other; and first and second external electrodes disposedoutside of the ceramic body, and connected to the first and secondinternal electrodes, respectively, wherein the ceramic body comprises anactive portion including the first and second internal electrodesdisposed to oppose each other with the dielectric layer interposedtherebetween to form capacitance, and a cover portion disposed in upperand lower portions of the active portion, the cover portion comprises aceramic-polymer composite filled with a polymer in the pores of thecover portion, and at least a portion of the polymer filled in the poresof the cover portion is physically isolated from the first and secondinternal electrodes.
 2. The multilayer ceramic capacitor of claim 1,wherein the dielectric layer of the active portion is free of thepolymer.
 3. The multilayer ceramic capacitor of claim 1, wherein adielectric composition of the cover portion and a dielectric compositionof the dielectric layer of the active portion are different from eachother.
 4. The multilayer ceramic capacitor of claim 1, wherein a marginportion is disposed on both sides of the active portion, the marginportion having a larger number of pores than the dielectric layer of theactive portion, and the margin portion comprises a ceramic-polymercomposite filled with a polymer in the pores of the margin portion. 5.The multilayer ceramic capacitor of claim 4, wherein a dielectriccomposition of the margin portion and a dielectric composition of thedielectric layer of the active portion are different from each other. 6.The multilayer ceramic capacitor of claim 4, wherein a dielectriccomposition of the margin portion and a dielectric composition of thedielectric layer of the active portion are the same as each other. 7.The multilayer ceramic capacitor of claim 1, wherein the cover portionhas a larger number of pores than the dielectric layer of the activeportion.
 8. The multilayer ceramic capacitor of claim 1, wherein thedielectric layer is interposed between the first and second internalelectrodes in a stacking direction, and the polymer is filled in thepores of the cover portion between dielectric grains in the stackingdirection.